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1.
Robert A. Moreau Kevin B. Hicks David B. Johnston Nathan P. Laun 《Journal of the American Oil Chemists' Society》2010,87(8):895-902
A study was conducted to examine the chemical composition of corn oil obtained after fermentation of corn to make fuel ethanol
via centrifugation and compare its composition to that of corn germ oil (commercial corn oil) and experimental corn oils.
The levels of free fatty acids in the post fermentation corn oil were high (11–16%), as previously reported. The levels of
free phytosterols and hydroxycinnamate steryl esters (similar to oryzanol in rice bran oil) were higher than those of corn
germ oil and were comparable to those of ethanol-extracted corn kernel oil. The levels of tocopherols were lower in post-fermentation
oil than in either corn germ oil or ethanol extracted corn kernel oil. The levels of lutein and zeaxanthin in post-fermentation
were much higher than those in corn germ oil and were comparable to those in ethanol-extracted corn kernel oil. Overall, exposure
to all upstream processes of a fuel ethanol plant, including high-temperature liquefaction, saccharification and fermentation
appeared to have the most notable effect on tocopherols, but it had little effect on the levels of free phytosterols, hydroxycinnamate
steryl esters, lutein and zeaxanthin. It may be desirable to recover these valuable functional lipids prior to using the post-fermentation
corn oil for industrial applications such as making biodiesel if a cost-effective recovery process can be developed. 相似文献
2.
All commercial corn oil is obtained by the hexane extraction of corn germ. The chemical composition of commercial corn oil
has been well characterized. This study was under-taken to quantitatively evaluate the lipid composition of corn oil obtained
by the ethanol extraction of ground, whole corn kernels. When corn oil was obtained by extracting ground corn kernels (ground
corn) with polar or nonpolar solvents, the resulting corn oil contained much higher levels of hydroxycinnamate steryl esters
(≈0.3%) than those found in commercial hexane-extracted corn (germ) oil (≈0.02%). The levels of valuable tocopherols and tocotrienols
were also significantly higher in kernel oil than in traditional corn germ oil. We previously reported that when corn oil
was obtained by extracting corn kernels with polar solvents, the oil contained two polyamine conjugates, diferuloylputrescine
and p-coumaroyl feruloylputrescine. In the current study, when ground corn was extracted with ethanol, the resulting corn oil contained
about 0.5% diferuloylputrescine and about 0.2% p-coumaroyl feruloylputrescine. This is the first study to quantify these unique compounds in corn oil extracted by new techniques.
This compositional information is important because this new oil is being considered for human food use. 相似文献
3.
Sezin Islamoglu Kadioglu Tri T. Phan David A. Sabatini 《Journal of the American Oil Chemists' Society》2011,88(6):863-869
An aqueous surfactant-based extraction system was developed for the extraction of corn oil from corn germ with anionic extended
surfactants. The surfactants used in this study were sodium linear-alkyl polypropoxylated polyethoxylated sulfates (C12,14–P10–E2–SO4Na and C10–P18–E2–SO4Na). Interfacial tension, critical microemulsion concentration (CμC), and optimum salinity values of the extended surfactants
with corn oil were determined. In the extraction process, the ground corn germ was shaken with predetermined surfactant and
salt concentrations at room temperature for 45 min. About 83%, the sum of total free oil and total oil-in-water emulsion,
of the corn oil was extracted from the corn germ using a formulation of 0.4% C12,14–P10–E2–SO4Na and 1% NaCl. A solid/liquid ratio of 1/10 performed best for efficient oil recovery. The chemical compositions of the extracted
corn oils were found to be similar to that of hexane extracted corn oil. 相似文献
4.
L. C. Dickey P. H. Cooke M. J. Kurantz A. McAloon N. Parris R. A. Moreau 《Journal of the American Oil Chemists' Society》2007,84(5):489-495
The increase in ethanol production from corn has prompted development of processes to separate corn germ. The corn germ co-product
would be a source of corn oil if a practical oil separation process were also developed. We carried out bench-scale corn-germ-pressing
experiments to determine the maximum potential oil recovery which were then used to estimate commercial germ crushing costs.
Corn germ was preheated in a microwave oven and oil was then extracted with a bench-scale press. Preheating the germ was necessary
to obtain good oil yields. The uniform heating of the microwave oven more closely resembles compressive heating of commercial
scale presses than does oven heating. Three different microscopic techniques were used to examine the effects of microwave
and conventional-oven heating on corn germ. Microscopy revealed that microwave heating heated oil in the germ more quickly
than the other components of the germ. Heating by both methods destroyed lipid body membranes and oil coalesced and pooled.
Less oil could be pressed from germ initially containing 3–6% moisture than germ containing 15–20% moisture. Maximum oil recovery
of about 65% was obtained for all germs tested when the optimum press temperature and germ feed moisture were used.
Mention of trade names or commercial products in this publication is solely for the purpose of providing specific information
and does not imply recommendation or endorsement by the US Department of Agriculture. 相似文献
5.
Robert A. Moreau Leland C. Dickey David B. Johnston Kevin B. Hicks 《Journal of the American Oil Chemists' Society》2009,86(5):469-474
A bench-scale aqueous enzymatic method was developed to extract corn oil from corn germ from either a commercial corn dry
mill or corn germ from a newly-developed experimental enzymatic wet milling process (E-Germ). With both types of germs, no
oil was extracted when acidic cellulase was the only enzyme used. Pre-treating dry milled corn germ by heating it in boiling
water or microwave pretreatment, followed by enzymatic extraction with the acidic cellulase resulted in oil yields of about
43% and 57%, respectively. A two-step process, combining both acidic cellulase and alkaline protease treatments, with no heat
pretreatment, achieved oil yields of 50–65% from dry milled corn germ and 80–90% from E-Germ.
Mention of trade names or commercial products in this publication is solely for the purpose of providing specific information
and does not imply recommendation or endorsement by the U.S. Department of Agriculture. 相似文献
6.
A comparison of commercial enzymes for the aqueous enzymatic extraction of corn oil from corn germ 总被引:5,自引:0,他引:5
An aqueous enzymatic method was developed to extract corn oil from corn germ. The basic steps in the method involved “churning”
the corn germ with various enzymes and buffer for 4 h at 50°C, and an additional 16 h at 65°C, followed by centrifugation
and removal of the oil layer from the surface. No hexane or other organic solvents are used in this process. By using oven-dried
corn germ samples (6 g) from a commercial corn wet mill, corn oil yields of about 80% were achieved using three different
commercial cellulases. A fourfold scale-up of the method (to 24 g of germ) resulted in oil yields of about 90%. Nine other
commercial enzymes were evaluated and resulted in significant but lower oil yields. In the absence of enzymes, oil yields
of 27 to 37% were achieved. The chemical compositions of hexane-extracted vs. aqueous enzymatic-extracted corn oils were very
similar. 相似文献
7.
Robert A. Moreau Anna-Maija Lampi Kevin B. Hicks 《Journal of the American Oil Chemists' Society》2009,86(12):1209-1214
This study compared the profiles of fatty acids, phytosterols, and polyamine conjugates in conventional commercial corn oil
extracted from corn germ and in two “new-generation” corn oils: hexane-extracted corn fiber oil and ethanol-extracted corn
kernel oil. The fatty acid compositions of all three corn oils were very similar and were unaffected by degumming, refining,
bleaching, and deodorization. The levels of total phytosterols in crude corn fiber oil were about tenfold higher than those
in commercial corn oil, and their levels in crude corn kernel oil were more than twofold higher than in conventional corn
oil. When corn kernel oil was subjected to conventional degumming, refining, bleaching, and deodorization, about half of the
phytosterols was removed, whereas when corn fiber oil was subjected to a gentle form of degumming, refining, bleaching, and
deodorization, only about 10% of the phytosterols was removed. Finally, when the levels of polyamine conjugates (diferuloylputrescine
and p-coumaroyl feruloylputrescine) were examined in these corn oils, they were only detected in the ethanol-extracted crude corn
kernel oil, confirming earlier reports that they were not extracted by hexane, and providing new information that they could
be removed from ethanol-extracted corn kernel oil by conventional degumming, refining, bleaching, and deodorizing. 相似文献
8.
Leland C. Dickey Michael J. Kurantz Nicholas Parris Andrew McAloon Robert A. Moreau 《Journal of the American Oil Chemists' Society》2009,86(9):927-932
More than 9 billion gallons of ethanol were produced in 2008, mostly from dry grind corn fermentation plants. These plants
are a potential source of substantial amounts of corn oil, if an economical method of separating it can be developed. In this
work, oil was separated from corn germ by aqueous enzymatic extraction (AEE). Batches of wet-milled corn germ in water were
preheated in a pressure cooker, ground in a colloid mill, and churned in a vertical column/mixing vessel system, after the
addition of enzyme. Nitrogen gas was then bubbled through the column removing an overflowing foam fraction which was subsequently
centrifuged to separate free oil. Using a newly commercialized enzyme complex it was found that 80% of the oil could be recovered
using a w/w ratio of enzyme solution to germ of 1:80. The low dose and low price of the enzyme complex leads to a cost estimate
of AEE of corn oil from germ, similar to the wet-milled germ extracted, cost competitive with expelled oil (with the separation
and drying of the foam protein), and feasible for commercialization in a dry grind plant retrofitted to separate germ. 相似文献
9.
Paul R. Pike El-Sayed M. Abdel-Aal Arthur R. McElroy 《Journal of the American Oil Chemists' Society》2007,84(7):663-667
Oat cultivar AC Vermont was malted to concentrate antioxidants, milled to fractionate only the endosperm portion and extracted
with methanol to isolate the crude antioxidants. The oat malt antioxidant fraction was assessed as a natural antioxidant based
upon enhancing the stability of corn oil against oxidation and compared to the synthetic antioxidant butylated hydroxytoluene
(BHT). The induction time (time required for the formation of 10 meq hydroperoxide per kilogram corn oil thermally oxidized)
was used to measure antioxidant activity of oat antioxidant or BHT. The protection factor achieved by crude oat malt antioxidant
extract concentrate at 0.26% (2,600 μg/g) was comparable to BHT (75 μg/g). The antioxidant activity of the oat and barley
malt extract concentrates was not significantly different. However, the extract concentrate of oat malt had 44% less color
compared to that of barley malt at equal concentrations showing its potential as a natural food antioxidant. 相似文献
10.
Antioxidant Activity of Raisin Extracts in Bulk Oil,Oil in Water Emulsion,and Sunflower Butter Model Systems 总被引:2,自引:0,他引:2
The antioxidant activities of the raisin extract (RE) in stripped corn oil, stripped corn oil emulsions, and sunflower butter
stored at 60 °C for up to 15 days was evaluated. Peroxide values and hexanal content were measured on a half day, 2 or 3 day
basis for the emulsion, sunflower butter, and bulk oil, respectively. The RE had the best antioxidant activity in the bulk
oil system. Statistical contrasts indicated the oxidation of bulk corn oil treated with RE was significantly (p < 0.001 and p = 0.044) lower than bulk oil and bulk oil treated with tertiary-butylhydroquinone (TBHQ), respectively. No differences (p = 0.15) in hexanal concentrations were observed in stored bulk oils treated with RE and TBHQ. However, both these materials
inhibited hexanal formation better (p < 0.001) when compared to the control corn oil. In contrast, 200 μg/g TBHQ had better (p = 0.0004) antioxidant activity than 3,000 μg/g RE in the oil in water(o/w) emulsion. No significant differences (p = 0.1637) in hexanal formation were observed in the emulsions treated with RE and TBHQ. However, the data indicated that
the RE treated emulsion did undergo more secondary oxidation than the emulsion treated with TBHQ beyond 110 h. The 3,000 μg/g
RE had antioxidant activity in sunflower butter, but was less effective than the 200 μg/g TBHQ and a lower RE concentration
(200 μg/g). The observations supported the hypothesis that RE has antioxidant activity in the multiple model systems. 相似文献
11.
超临界CO2萃取玉米胚芽油工艺的研究 总被引:9,自引:0,他引:9
本文研究采用超临界CO2从玉米胚芽中萃取油品的工艺条件,运用响应面法探讨了萃取压力、萃取温度和物料粒径在油品产率为90%时对CO2消耗量的影响,确定了最佳工艺参数,分析比较了超临界CO2萃取、正己烷索氏萃取和压榨三种方法对油品质量和脂肪酸组成的影响。 相似文献
12.
The sequential extraction process (SEP) uses ethanol to extract oil and protein from cracked, flaked, and dried corn, and
the dried corn simultaneously dehydrates the ethanol. Value-added co-products are possible, potentially making production
of fuel ethanol more economical. The effects of solvent-to-corn (S/C) ratio, corn moisture content (MC), and number of extraction
stages on ethanol drying, oil recovery, and protein loss during the simultaneous oil extraction/water adsorption step of SEP
were evaluated. Extractions were carried out by using both aqueous ethanol and ethanol/hexane blends at 56°C. The S/C ratios
tested were 3∶1, 2∶1 (control), 1.5∶1, and 1∶1 (w/w). More anhydrous ethanol, greater oil yields, and less co-extracted protein
were obtained with higher S/C ratios. Less anhydrous ethanol and lower moisture adsorption capacities were obtained when the
corn MC was ≥1.12%. Oil yields gradually decreased with drier corn, whereas protein loss increased when corn MC was <1.12%.
Reducing the number of extraction stages from seven (original SEP) to five did not affect ethanol drying capability, oil yields,
and protein co-extracted with oil. Using ethanol/hexane blends resulted in more anhydrous ethanol, higher oil yields, and
less protein co-extracted with oil. 相似文献
13.
Sandra Majoni Tong Wang Lawrence A. Johnson 《Journal of the American Oil Chemists' Society》2011,88(3):425-434
Oil recovery from corn fermentation co-products can provide feedstock for biodiesel production. The effects of physical and
chemical processes on oil recovery from condensed corn distillers solubles (CCDS) were investigated. Heating disrupted physical
interactions in the CCDS and increased oil recovery by 2.5-fold when temperature was increased from 25 to 59 °C. Oil recovery
at acidic pH conditions was significantly greater than at alkaline pH. Oil recovery at alkaline pH was increased by heating
and addition of the reducing agent, sodium metabisulfite. Oil extraction using polar solvents isopropanol and butanol achieved
greater than 80% oil recovery. When oil was co-extracted with zein using hexane and ethanol as co-solvents, the greatest total
oil recovery was achieved, 89%. Churning CCDS at pH 3.5, 50 °C for 3 h achieved up to 80% oil recovery. This study provides
data for designing further effective methods for oil separation from corn ethanol co-products. 相似文献
14.
Corn oil was extracted from whole ground corn using ethanol as the solvent. The yield of oil was measured as a function of
temperature, time of extraction, solvent-to-solids ratio, and ethanol concentration. Optimal conditions were a solvent-to-solids
ratio of 4 mL/g corn, an ethanol concentration of 100%, 30 min of extraction time, and a temperature of 50°C. Under these
conditions, a single batch extraction yielded ≈3.3 g oil/100 g corn, equivalent to 70% extraction efficiency. A three-stage
extraction, where the same corn was exposed to fresh ethanol, resulted in a yield of ≈4.5 g/100 g corn (2.5 lb/bu of corn),
equivalent to 93% recovery of the oil in corn. When anhydrous ethanol was used to repeatedly extract fresh corn, moisture
was absorbed linearly by ethanol from the corn in successive stages, which, in turn, decreased oil yield and increased nonoil
components in the extract. 相似文献
15.
Samples of corn germ were obtained from a commercial corn wet mill (factory dried to about 3% moisture) and a commerical corn
dry mill (undried, produced in the mill with about 13% moisture). The germ samples (200 g each) were cooked for various times
in either a conventional oven at 180°C or a microwave oven at 1500 W. Bench-scale single screw pressing was then performed.
With the dry milled corn germ, no oil was obtained from the uncooked germ. A maximal yield of about 5% oil [26% of total oil
recovery (TOR), relative to hexane extraction] was obtained by cooking the dry-milled germ for 6.5 min in a conventional oven
at 180°C before pressing. A maximal yield of about 7% oil (37% TOR) was obtained by cooking the dry-milled germ for 4.5 min
in a microwave oven at 1500 W before pressing. With the wet-milled germ, yields of about 7% oil (18% TOR) were obtained with
the uncooked germ and yields increased to a maximum of about 22% oil (56% TOR) by cooking in a conventional oven at 180°C
for 5 min or a maximum of about 17% oil (44% TOR) by cooking for 4 min in a microwave oven at 1500 W. These results indicate
that microwave and conventional oven cooking are both effective pretreatments before pressing. Microwave preheating resulted
in higher oil yields with dry-milled germ, and conventional oven pretreatment resulted in higher oil yields with factory-dried
wet-milled corn germ. 相似文献
16.
Several new processes for milling corn have been developed recently specifically to isolate germ as a value-added co-product
and improve the profitability of dry-grind ethanol production. The present work used modified and conventional corn milling
technologies to recover germ fractions from corn kernels using either wet or dry separation processes. This study determined
the quality, composition, and yield differences among the corn germ produced and compared these properties with those of the
conventional wet- and dry-milled germ. A method for calculating the estimated market value for germ produced by the alternative
processing methods is given. There were significant differences in the oil, protein, starch, and ash compositions and in the
estimated market values among germ fractions produced by the alternative milling processes. The different germ fractions produced
(including the traditional wet-and dry-milled) were found to contain 18–41% oil, 13–21% protein, and 6–21% starch, depending
on the milling process used. The estimated value of germ from these processes varied from as low as $0.058/lb ($0.128/kg)
to a maximum of $0.114/lb ($0.251/kg), showing that the specific process used to produce the germ will have the major impact
on the overall economics of the ethanol process. 相似文献
17.
Malondialdehyde (MA) formed in linolenic acid, linoleic acid, corn oil and beef fat upon photoirradiation was determined by
gas chromatography (GC). The MA produced was reacted with methylhydrazine to give 1-methyl-pyrazole and was subsequently analyzed
on a GC equipped with a nitrogen-phosphorus specific detector and a fused silica capillary column. MA values determined by
this method correspond to free or unbound MA levels. Linolenic and linoleic acids produced 867 μg MA/g and 106 μg MA/g, respectively.
Oleic and stearic acids did not produce detectable levels of MA upon photoirradiation. Amounts of MA produced after eight
hour irradiations of corn oil and beef fat were 56.24 μg/g and 25.01 μg/g, respectively. Some photoreaction products in irradiated
corn oil also were identified as methylhydrazine derivatives. 相似文献
18.
A Novel Method for the Production of Biodiesel from the Whole Stillage-Extracted Corn Oil 总被引:1,自引:0,他引:1
Hossein Noureddini Santosh R. P. Bandlamudi Emily A. Guthrie 《Journal of the American Oil Chemists' Society》2009,86(1):83-91
The extraction of corn oil from whole stillage and condensed distillers’ solubles (CDS) with hexane and its conversion to
biodiesel were investigated. The analysis of the extracted oil showed 6–8 wt.% free fatty acid (FFA) in this oil. Acid, base,
acid–base, and acid–base catalyzed transesterifications with intermediate neutralization with anion exchange resin were investigated.
Experiments were performed with model corn oil substrates which contained 1.0–6.0 wt.% FFA. The effect of catalyst at 0.50–1.25 wt.%
was studied at a 1:8 oil/methanol molar ratio. At 6.0 wt.% FFA concentration, the acid-catalyzed scheme was slow and resulted
in less than 20% yield after 4 h, while the base-catalyzed was mostly consumed by the FFA and very little conversion was achieved.
The acid–base catalyzed scheme succeeded in reducing the FFA content of the oil through the acid-catalyzed stage, and yields
in excess of 85% were achieved after the second stage of the reaction with a base catalyst. However, formation of water and
soap prevented the separation of product phases. An alternative acid–base catalyzed scheme was examined which made use of
a strong anion exchange resin to neutralize the substrate after the initial acid-catalyzed stage. This scheme resulted in
the effective removal of the acid catalyst as well as the residual FFA prior to the base-catalyzed stage. The subsequent base-catalyzed
stage resulted in yields in excess of 98% for a 7.0 wt.% FFA corn oil and for the corn oil extracted from CDS. 相似文献
19.
Sandra Majoni Tong Wang Lawrence A. Johnson 《Journal of the American Oil Chemists' Society》2011,88(4):523-532
The objective of this study was to determine the effect of enzyme hydrolysis of various corn components on oil recovery from
condensed corn distillers solubles (CCDS). Hydrolysis with a commercial protease significantly increased oil recovery as the
enzyme concentration increased, with the greatest oil recovery being 70% at 10% v/w (dry weight basis) enzyme concentration.
Increasing centrifugal force from 8,500 to 12,240×g was only slightly effective for the non-enzyme treated samples. Reducing CCDS particle size by grinding with a mortar and
pestle increased oil recovery to 83% when an enzyme combination of a commercial cellulase mixture and a protease was used.
Particle size reduction of CCDS by high-speed blending resulted in low oil recovery, but the oil recovery was significantly
improved after enzyme treatment. Zein-lipid interaction was very strong when tested in a model system, with only 10% of the
oil being freed by centrifugation alone. Following enzyme hydrolysis of the zein-oil complex with a protease, oil recovery
was increased to 97%. Overall, enzyme hydrolysis and further particle size reduction showed a small, albeit statistically
significant, effect in increasing oil recovery from CCDS. These small increases may not justify the use of enzymes or processing
modifications to reduce particle size in the ethanol industry, nonetheless, these data may provide a reference or insight
to design more effective treatments for oil recovery. 相似文献
20.
Robert A. Moreau Keshun Liu Jill K. Winkler-Moser Vijay Singh 《Journal of the American Oil Chemists' Society》2011,88(3):435-442
During the dry grind ethanol process, ground corn is fermented and the major co-product is a feed called distillers dried
grains with solubles (DDGS). This study investigated the changes that occur in the composition of corn oil that can be extracted
from various process fractions during the dry grind ethanol process. In the first part of this study, samples of distillers
dried grains, thin stillage, condensed distillers solubles (also known as syrup), and DDGS were obtained from 7 dry grind
ethanol plants. The levels of deleterious free fatty acids were high (>7%) and those of valuable total phytosterols were also
high in all fractions (>2%). In the second part of this study, changes in the content and composition of the fatty acids,
phytosterols, tocopherols and tocotrienols were quantitatively analyzed in crude oil samples extracted from nine dry grind
process fractions from three commercial ethanol plants. Fatty acid and phytosterol composition remained nearly constant in
all nine fractions, although some significant variations in phytosterol composition existed among the fractions. Examination
of the tocopherols and tocotrienols revealed that γ-tocopherol was the most abundant tocol in ground corn but an unknown tocol
became the predominant tocol after fermentation and persisted in the remaining processing fractions and in the final DDGS
product. Overall, the remaining majority of tocols remained relatively unchanged. 相似文献